1. Field of the Invention
The present invention relates to a hose connecting assembly, where a hose connecting tube is pressed into a hose to ensure connection with the hose.
2. Description of the Related Art
There are known hose connecting assemblies, such as those disclosed in JAPANESE PATENT LAID-OPEN GAZETTE No. 9-159077. FIG. 26 is a partly broken front view illustrating a prior art hose connecting assembly including a branched pipe 100. Referring to FIG. 26, the hose connecting assembly includes the branched pipe 100 having three branched portions 101, 102, and 103, and hoses 111, 112, and 113, into which the branched portions 101, 102, and 103 are respectively pressed. A pair of ring-shaped projections 104 and 105 are formed around the circumferential face of each of the branched portions 101, 102, and 103. The ring-shaped projections 104 and 105 have a triangular cross section and are arranged at a certain interval. FIG. 27 is an enlarged cross sectional view illustrating the branched portion 101. As shown in FIG. 27, the ring-shaped projections 104 and 105 respectively have truncated cone faces 104a and 105a, which have outer diameters tapered toward the free end of the branched portion 101, and acute-angled faces 104b and 105b, which extend between outer edges of the truncated cone faces 104a and 105a and the base circumference of the branched portion 101, and which have an acute angle with the truncated cone faces 104a and 105a, respectively. The hose 111 includes an inner layer 111a made of an EPDM rubber, a thread-reinforced layer 111b made of braided or spirally networked reinforcing threads, and an outer layer 111c made of an EPDM rubber.
In the prior art hose connecting assembly, when the branched portion 101 is pressed into the hose 111, the ring-shaper projections 104 and 105 apply the force that expands the inner diameter of the hose 111. This force causes a large reaction force of the thread-reinforced layer 111b to limit the expansion. The hose 111 thus securely clamps the branched portion 101. Since the hose 111 is secured to the branched portion 101 with a large force, this arrangement ensures the secure connection of the hose 111 with the branched portion 101 without using any clamps and by simply pressing the branched portion 101 into the hose 111.
In the prior art hose connecting assembly, since the hose 111 is joined with the branched portion 101, without using any clamping fixtures such as clamps, and by simply pressing the branched portion 101 into the hose 111, a tight seal as well as the large securing force is required. The hose connecting assembly is required to ensure the tight seal even at places where the hose 111 is vibrated against the branched portion 101, for example, in an engine room of an automobile, and at places where a rotating force is applied to the hose 111.